This invention relates generally to dual in-line package (DIP) receptacles and more particularly to low profile DIP receptacles having a pair of rows of contacts therein with each pair of contacts engaging both sides of the DIP leads with metal surfaces.
Dual in-line packages comprise a fairly standardized means of packaging circuit elements which can consist of anything from a plurality of discrete circuit components to a large scale integrated circuit chip. The DIP package consists of a main plastic body having two rows of terminals extending from the side thereof and bent downwardly. These external leads are usually spaced about 0.100 inches apart and with the two rows being spaced approximately 0.300 inches apart. The number of leads or terminals in each row of the DIP terminals can vary greatly, depending upon the contents of a DIP package.
In some applicatons the DIP package is mounted directly on the circuit board either through plated through holes in the board with the leads of the DIP extending through the plated through holes in the board or into miniature type sockets which in turn are fitted into holes in the substrate or printed circuit board. By various soldering techniques the DIP can be then permanently secured to the board. However, such installations present various types of problems including the possibility of damage to one of the fragile DIP leads during insertion into the printed circuit board or the burning or damaging of such DIP leads during the soldering operation. A further disadvantage is that in the event of failure of the circuitry contained within the DIP a difficult problem of replacement is presented. The insertion of the DIP leads directly into the board and retention therein based solely on frictional engagement with the circuit board hole presents some problems because of the fragility of the DIP leads and the force required to frictionally insert them in the holes of a substrate without damaging or breaking the DIP leads.
Various types of sockets are available on the market which are mountable on the surface of a printed circuit board or in apertures or plated through holes formed therein or holes formed therein which contain separately insertable miniature type sockets to receive the DIP leads. The DIP itself is then mounted upon the socket or the female receptacles of the terminals mounted in the plastic housing of the socket.
However, even with the use of a socket certain problems remain unsolved with present day structures. More particularly, such sockets frequently employ housings having apertures therein into which terminals are inserted with the posts extending through one side thereof and then in turn secured within apertures in the circuit board. Such terminals, when inserted into a socket frequently provide the means for solder to leak up through the terminals and wick into the DIP lead terminals and either provide short circuits therein or prevent proper insertion of the DIP lead terminals into the socket. Another problem presented with the many presently available DIP sockets is the fact that the DIP terminals are inserted into apertures in the socket which have metal contacts on one side and plastic on the other. In other words, DIP lead terminals are wedged in-between a metal surface and a plastic surface, thereby reducing the chance for good, permanent, reliable electrical contact between the DIP lead terminals and the desired circuit paths on the printed circuit board.
Even where sockets are employed which overcome most of the foregoing problems there frequently remains the problem of insertion force. More specifically it is necessary that a certain normal force exist between the contacts within the socket and the terminals of the DIP lead in order to maintain proper electrical contact. However, such force is cumulative in that each DIP terminal has such a force exerted thereon and the total insertion force of the DIP into the socket can be very considerable, again often resulting in damage to the DIP leads. Misalignment of the terminals of the DIP, which frequently occur, can also cause damage to the terminals of the socket which by necessity are fragile in order to keep the total insertion force of the DIP below a certain feasible value.